Measurement of ocular transmission in living human eyes with a double-pass system

Abstract

PurposeTo develop a methodology based on a double-pass system to obtain useful information about the transmission of ocular media, performing noninvasive measures in vivo.\n\nMethodsThis noninvasive procedure consists of recording double-pass images at different voltages of a laser diode of 780 nm and the determination of the scattering in an area between 25 and 35 arc minutes of each image.\n\nResultsOcular scattering showed a linear behavior respect to the voltage of the laser and the slope of the linear fit was proportional to the transmittance squared of the media evaluated. The relationship between the ocular light scattering of the images and the transmittance values of several filters located into an artificial eye was used as a calibration function. The measurements performed in a group of ten subjects with ages between 25 and 45 years old presented a mean direct transmittance of the whole eye including retina of 42.7 %, which agrees with the bibliography. No differences between dark eyes and light eyes were found.\n\nConclusionWe have developed a method to determine the transmittance of the human eye in vivo for a wavelength of 780 nm using the double-pass method, commonly used for the determination of the optical quality of an eye.